Field of the Invention
The present invention relates to wireless communications, and more specifically, to a method and apparatus for configuring a cell in a wireless communication system.
Related Art
Universal mobile telecommunications system (UMTS) is a 3rd generation (3G) asynchronous mobile communication system operating in wideband code division multiple access (WCDMA) based on European systems, global system for mobile communications (GSM) and general packet radio services (GPRS). A long-term evolution (LTE) of UMTS is under discussion by the 3rd generation partnership project (3GPP) that standardized UMTS.
The 3GPP LTE is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
Carrier aggregation (CA) may be introduced. In CA, two or more component carriers (CCs) are aggregated in order to support wider transmission bandwidths up to 100 MHz. A UE may simultaneously receive or transmit on one or multiple CCs depending on its capabilities. A Rel-10 UE with reception and/or transmission capabilities for CA can simultaneously receive and/or transmit on multiple CCs corresponding to multiple serving cells. A Rel-8/9 UE can receive on a single CC and transmit on a single CC corresponding to one serving cell only.
A cell is combination of downlink resources and optionally uplink resources. The linking between the carrier frequency of the downlink resources and the carrier frequency of the uplink resources is indicated in the system information transmitted on the downlink resources. A serving cell may consist of one DL CC and one UL CC. Or, a serving cell may consist of one DL CC only.
There may be a plurality of serving cells, and the plurality of serving cells consists may consist of one primary cell (PCell) and at least one secondary cell (SCell). A method for configuring a SCell efficiently may be required.